LOGAR PROVINCE, Afghanistan - They were just getting ready to leave for the day when the rounds hit.

There were at least three of them, said Staff Sgt. Andrew Garza, Prime Power noncommissioned officer in charge, Forward Operating Base Shank, 249th Engineer Battalion, United States Forces-Afghanistan.

Garza and his coworker, Pfc. Tyrone House, power optimization specialist, 249th Engineer Battalion, immediately followed the official procedure for incoming fire; they hit the ground.

One of the rounds had landed near a group of tents, where the shrapnel tore into an electrical transformer.

The transformer blew up, with an explosion that "damn near the whole base heard," said Garza, a native of Fort Belvoir, Texas.

After the all-clear, they left their protective bunker and got to work replacing the damaged transformer. With the help of electrical contracting companies Inglett and Stubbs International and IAP Worldwide Services, they brought power back to the tents in about four-and-a-half hours.

Garza and House are currently working to remove hundreds of electrical spot generators from Shank and bring the base onto prime power. Prime power is a more efficient, cost-effective power plant system that will replace spot generation and keep more fuel trucks off the road, House said.

House and Garza's work removing generators has brought high returns. In the two months they've been at Shank, they have literally saved millions of dollars in fuel costs, Garza said.

The spot generators, which are most efficient when running at 80-90 percent capacity, are seriously underloaded and consume much more fuel than necessary to power the base, he added.

But it's more than money. The main benefit in less fuel consumed is that fewer fuel trucks are on the road, which means fewer Soldiers in harm's way, said House.

"It's an amazing amount of good that we get to do for the mission," Garza said.

House, a former corrections officer in Montgomery, Ala., has taken to his job with eagerness, having seen the importance of prime power to the base.

"I saw the power lines, but I didn't really understand the concept of what it is, but now I've been in this job and seen how important prime power really is," House said. "It's a great job."

While Shank may not be the most comfortable place to be stationed, the mission is still going to be accomplished, House said.

"Our main goal is to get most of this camp on prime power," House said. "We can't let [indirect fire] affect what we do, as far as it being our primary mission. You just have to keep driving on."

Two days after the transformer was hit, another round shook House and Garza's office, pounding a crater into a concrete barrier across the road.

When the debris stopped falling, Garza ran to help the medics with a few lightly- injured personnel. Both were checked and cleared for minor injuries. On the medics' orders, they took the day off.

Then they went back to work.